15th International Ceramics Congress
Plenary Lectures
ABSTRACTS
C:PL1 High-Pressure Materials Synthesis - A Guideline for the Discovery of Advanced Ceramic Nitrides
R. RIEDEL, Department of Dispersive Solids, Institute of Materials Sciences, Technical University of Darmstadt, Darmstadt, Germany (World Academy of Ceramics Prize Laureate Lecture)
High-pressure synthesis routes enable the access to a broad variety of novel nitride-based materials with properties far beyond that of the state of the art. The ultimate goal of our studies is to advance the knowledge and understanding of inorganic nitrides, oxynitrides and nitride-based (nano)composites synthesized under high-pressure and high temperature conditions. The discovery of novel nitrides will open space for new fundamental materials science studies on the one hand and application-oriented research on the other hand. Our research is part of the materials driven technology, which is an essential requirement for the future demands with respect to the development of new technologies. Binary, ternary and multinary nitrides or oxynitrides are in the focus of our studies. Theoretical predictions of novel metal or non-metal nitride solid-state structures guide the experimental studies. The use of a large volume press allows to produce new materials in amounts suitable for further mechanical and functional characterization. Molecular single source precursors are synthesized and transformed to inorganic solid nitrides as starting materials. Special emphasis is placed on (i) fundamental questions regarding pressure-temperature phase relations, (ii) nitrides, which have been predicted but not synthesized yet, and (iii) nitride-based (nano)composites which combine at least two binary high-pressure phases in one material. The novel nitrides are evaluated in terms of their challenging and technologically relevant properties including (i) thermodynamic stability/metastability and (ii) structural (hardness) as well as functional (optoelectronic) properties. Finally, our research contributes to extend the “Nitride World” and to deliver perspective materials based on the inorganic nitride family with advanced functionality and exceptional levels of performance for application in the key technologies of the 21st century.
C:PL2 Removing Roadblocks and Opening New Opportunities for MXenes
M.W. BARSOUM1, Y. GOGOTSI1, 2, 1Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA; 2A.J. Drexel Nanomaterials Institute, Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA (World Academy of Ceramics Prize Laureates Lecture)
The 2D carbides and nitrides, known as MXenes, are among the most recent, but quickly expanding material families. The field is experiencing very fast growth with the number of papers on MXenes roughly doubling every year since their discovery in 2011. Great progress in synthesis and control of MXene properties has been achieved since. Synthesis of numerous of theoretically predicted MXenes, including ordered solid solutions and high-entropy structures, led to exploration of numerous applications. MXenes are not only promising candidates for energy storage and related electrochemical applications, such as electrocatalysis, but also applications in optoelectronics, plasmonics, electromagnetic interference shielding, medicine, sensing, catalysis and water desalination. This article addresses some of the challenges that MXenes, as a still young family of materials, face, describes the state-of-the art in the field and outlines future research directions. We particularly focus on key material manufacturing and stability issues. We describe the scalable synthesis of MXenes by selective etching in aqueous acidic solutions; alternative synthesis methods, particularly fluorine-free synthesis; delamination without the use of organic intercalants; and improving the environmentally stability and shelf life of MXenes in colloidal suspensions. Finally, we discuss the current understanding of electronic transport in MXene films, which is of critical importance for many MXene applications.
C:PL3 C-Axis Aligned Crystalline Indium-Gallium-Zinc Oxide Ceramics and Oxide Semiconductor LSI as Countermeasures against Global Warming
SHUNPEI YAMAZAKI, K. Kato, T. Onuki, D. Shimada, H. Kimura, F. Isaka, R. Hodo, H. Baba, T. Nakayama, H. Kunitake, Semiconductor Energy Laboratory Co., Ltd., Atsugi, Kanagawa, Japan
Global and Japan’s annual power consumptions of IT equipment in 2050 are predicted to be nearly 200 times as high as present global and Japan’s total annual power consumptions.[1] Therefore, global warming, which is an urgent issue discussed in the United Nations, would continue to be on rise. It is clear that countermeasures for this issue from the hardware perspective are most necessary.
We have researched and developed crystalline oxide semiconductor (OS) ceramics, especially c-axis aligned crystalline In–Ga–Zn oxide (CAAC-IGZO) ceramics, FETs. CAAC-IGZO FETs exhibit an extremely low off-state current on the order of yA (1024 A)/m at 85C, which is 10 digits lower than that of Si FETs.[2] Moreover, a scaled-down CAAC-IGZO FET with a gate length of 13 nm for 5G communication has achieved a cutoff frequency Fcutoff, which is an index of high-speed operation, of 55 GHz.
The operation efficiency of the combination of a normally-off CPU and an AI accelerator fabricated using OS LSI can be 100 TOPS/W or higher, which is 10 or more times as high as the potential operation efficiency limit of the combination of a CPU and an AI accelerator fabricated using Si LSI, 10 TOPS/W. Moreover, the combination of the normally-off CPU and the AI accelerator fabricated using OS LSI even has a possibility of achieving an operation efficiency of 1 POPS/W. The use of OS LSI enables reductions in total power consumptions of all LSI devices, including super computers. The achievement of extreme power saving owing to OS LSI installed in super computers used for AI processing will make AI and Internet of Things become more familiar in the future. Therefore, OS LSI may be the only answer to the global warming countermeasures. OS LSI is suitable for all displays, AR/VR applications, DRAM, and 3D OS NAND. This presentation introduces crystalline IGZO ceramics as one of the future key technologies, and shows its physical property and its LSI and display potential applications.
Reference
[1] Center for Low Carbon Society Strategy, Japan Science and Technology Agency, “Impact of Progress of Information Society on Energy Consumption (Vol.1),” 2019, https://www.jst.go.jp/lcs/pdf/fy2018-pp-15.pdf [published in Japanese].
[2] S. Yamazaki, “Challenge of crystalline IGZO ceramics to silicon LSI,” speech at Science Seminar 2018 held
by Japan-Sweden Foundation at Embassy of Sweden, Alfred Nobel Auditorium on November 26, 2018